Back in season seven, Mark Gatiss reintroduced classic Doctor Who villains the Ice Warriors in “Cold War,” an episode I was gaga over. A big part of my love revolved around its infusion of ’80s nuclear paranoia, which at the time seemed something of a distant memory. My, how just a few years can see us tumbling backward. “Empress of Mars,” which is in no way a sequel to “Cold War” (indeed, it takes place a hundred years before its predecessor), is another score for Gatiss, and enough so that we must forgive him for last season’s dire “Sleep No More.” “Empress” is a sleek tale of honor, loyalty, and redemption told through the filter of science-fiction mavericks such as Burroughs, Verne, and Wells.

The action kicks off in the present day at NASA, which the Doctor, Bill, and Nardole have infiltrated seemingly for no other reason than because they can. A probe called the Valkyrie is sending back images from a previously unseen area of the planet, and the first one shocks everyone in the room: It’s a landscape across which is written “God Save the Queen.” The Doctor wastes no time taking his posse to the planet, albeit in 1881, which is when the TARDIS says the message was created. (Must be a handy new feature that we’ll likely never see again.) They materialize underground in an elaborate cave system, replete with oxygen, which the Doctor credits the “indigenous Martians” with engineering.

Without warning, Bill tumbles down a shaft and Nardole rushes back to the TARDIS to get rescue gear … only for the TARDIS to dematerialize, seemingly of its own accord. We never do get a solid reason for why that happens, but the result of the action is probably the only reason we need: Missy. The craft returns to the school and the only person Nardole can turn to is inside the vault. She’s happy to help. We see neither of them again until the end of the episode, when Nardole nervously greets the Doctor and Bill. As they step through the door, they see Missy sheepishly peeking from behind the time rotor. The Doctor quietly informs her that “this can’t happen” and that she must go back into the vault. She comes closer to him, seemingly most concerned for his health and safety, and there’s a moment of pure electricity between the Doctor and his old nemesis. What is going on there?

On one hand, it’s difficult to believe Missy has changed. Surely this is an elaborate ruse, right? The idea that she’s putting on a show in order to escape back out into the universe seems the most plausible scenario. But the more interesting possibility is that she actually has undergone a transformation of spirit. We’re nearing the end of not just Peter Capaldi’s Doctor but also Michelle Gomez’s Missy. Would it not be poetic to have experienced some genuine change in this character, perhaps for the first time in over 40 years?

The Doctor: “The indigenous species — an ancient reptilian race that built themselves a sort of biomechanical armor for protection. The creature within is at one with its carapace. The Ice Warriors — they could build a city under the sand, yet drench the snows of Mars with innocent blood. They could slaughter whole civilizations, yet weep at the crushing of a flower.”

Back in the caves. the Doctor runs into a hulking Ice Warrior while Bill encounters Captain Catchlove (Victoria’s Ferdinand Kingsley), decked out in a steampunk spacesuit that’s sure to have cosplayers working overtime. But the two are not enemies as it first appears. Colonel Godsacre (Anthony Calf) was stationed in South Africa where he found a Martian vessel. Inside was an Ice Warrior in a deep sleep. They dubbed him Friday and helped him repair his ship, and he in return built the Gargantua, a piece of mining equipment cobbled together from the Martian ship’s weaponry. The group returned to Mars to loot it for promised riches that weren’t to be found, and they’ve been stranded ever since.

The battle-scarred Friday (Richard Ashton) is a much different Ice Warrior than any we’ve seen before, though still seemingly built on little cues from Doctor Who’s past. See, in the classic series, the Ice Warriors were villains for two Patrick Troughton serials (“The Ice Warriors” and “The Seeds of Death”), but when they returned a few years later in Jon Pertwee’s “The Curse of Peladon,” they’d cleaned up their act and joined the Galactic Federation. They were suddenly the good guys! Friday exists in a state in between the two extremes — and with good reason, as we find out at the close of the episode. He says, “I am old and tired and spent” and yet catches a falling plate in mid-air. All is not entirely as it seems. Friday has used the Victorian soldiers not just as a way back to Mars, but also to unwittingly help him find and excavate his sleeping Queen.

The Gargantua does precisely what Friday had planned, which is unearth the Ice Queen’s resplendent tomb. Soon, greed takes hold of soldier Jackdaw (Game of Thrones’ Ian Beattie), and he pries jewels from the sarcophagus which leads to the Queen’s awakening and his death. The female of the species is apparently more deadly than the male, and Iraxxa (Adele Lynch) is every bit the warrior as her male subordinates, if not more so. She’s a one-woman killing machine, and perhaps the episode’s greatest bit of revisionism comes in the form of what the Ice Warrior weapons can do, which is best described as delightfully horrific: They instantaneously crunch the body into a bouncy cube! It looks terribly painful, but it happens so fast it also seems unlikely the victims feel anything.

The Doctor brokers a truce by explaining that the Martian empire is no more, which Friday confirms. Iraxxa looks to Bill for solidarity and counsel as they are surrounded by “noisy males.” Sadly, a soldier fires, though it’s unclear if it was by accident or design. Nevertheless, war is declared and Catchlove takes command of the group, exposing Godsacre’s secret — he’s a coward and a deserter and was hanged for his crimes, only the rope didn’t kill him, just left him with a nasty scar. He places the Colonel along with the Doctor and Bill into confinement.

Bill (to Godsacre): “Listen, I’m going to make allowances for your Victorians attitudes because … well, you actually are Victorian.”

A battle ensues, with more Warriors rising up through the ground itself, mercilessly slaughtering the Victorians. Friday wishes to work with the Doctor, and Bill brings the violence to a standstill by stepping in and again grabbing the Queen’s attention … but it’s not enough. The Doctor threatens to bring the entire cave system crashing down with one shot from the Gargantuan, burying everyone in ice. Before anything of the sort can happen, Catchlove puts a sword to Iraxxa’s throat, but Godsacre surprises everyone — with a bullet to the Captain’s gut.

Godsacre: “Some time ago, I was hanged for cowardice. The execution took longer than expected, and I fear I have not used my time well. I should be happy for you to complete the work they failed to do so long ago.”

The Doctor sends a transmission to the stars, and within seconds someone sends a message back, and old-school fans either shrieked with delight or fell out of their chairs: It’s Alpha Centauri, the hermaphroditic hexapod, voiced by none other than 92-year-old Ysanne Churchman, who voiced the absurdly phallic creature back in the ’70s. The story ends up a ret-con detailing the Ice Warrior transition between the Troughton and Pertwee eras. Godsacre, now beholden to the Ice Queen, helps to place a monument on the planet’s surface so they can be found: It’s the “God Save the Queen” message that brought the Doctor to Mars in the first place.

Odds and Ends

• Ace Bits: The Queen is a standout; Lynch and Ashton do incredible work under heavy makeup and costumes (she’s reminiscent of the Borg Queen from First Contact, yes?); the ongoing classic movie jargon from Bill that culminates in the Doctor making a Frozen joke.

• Naff Bits: That awkward moment when Bill seems to have no knowledge of Robinson Crusoe. Perhaps it was meant to contrast with her movie knowledge?

• Anthony Calf, who may be the episode’s MVP, made his television debut in the 1982 Doctor Who serial “The Visitation.”

• The line “RHIP — rank has its privileges” was first said by Captain Mike Yates in “Day of the Daleks.”